High density integrated circuit packages, known as flat packs or formed packages for surface mounting, are widely used in many applications. Typically, such packages have a relatively large number of parallel leads extending from each of the four sides of a rectangular package. It is important for the leads to be properly spaced from one another, and to remain co-planar at the time the packages are attached to printed circuit boards.
Standard manufacturing techniques for high density surface-mounted flat packages typically utilize the formation of plastic tie bars around the ends of the leads, or attached to the bottom side of the ends of the leads during manufacture of the packages. This is done to prevent misalignment of the leads or subsequent damage during handling of the package prior to forming or configuring the leads to the shape required for attachment of the package to a printed circuit board. These tie bars are severed from the leads at the forming stage of operation; so that once the leads are formed, the formed leads are physically independent of one another. The result is a relatively high succeptability to bending or misalignment of the leads during handling of the formed package prior to its attachment to a printed circuit board. Because the leads are physically independent of one another, mishandling of the package prior to its connection to a printed circuit board can cause one or more of the leads to be bent so as not to be co-planar with the rest of the leads. This results in subsequent attachment difficulties to printed circuit boards.
It is desirable to provide a structure which will significantly reduce the co-planarity and bent lead failures resulting from the mishandling of formed high density integrated circuit packages prior to attachment of such packages to a printed circuit board.